Question #4014f

1 Answer
Nov 24, 2017

Si-30 = 29.9344 amu, 3.2%

Explanation:

The way to calculate isotopic mass is with this formula:

molar mass=(amu% abundance), so we can start plugging in some numbers using the molar mass of Silicon from the periodic table and the numbers provided:

28.0855=(27.97690.922)+(28.97650.046)+(x0.032)

I got 0.032 from subtracting 0.922+0.046 from 1 (because % abundance needs to add up to 100%).

Now that we have the numbers plugged in, we solve algebraically:

Step 1: Simplify right side

28.0855=27.1276+(x0.032)

Step 2: Subtract 27.1276 from both sides

0.9579=x0.032

Step 3: Divide by 0.032 on both sides to get isotopic mass of Si-30

29.9344=x

Hope this helped!